1. Field of the Invention
This invention relates to a method for the production of cystamine and an alkylene oxide adduct of cystamine, an additive for an aqueous lubricant, and an aqueous lubricant containing the additive.
2. Description of the Prior Art
Heretofore, cystamine has been produced by oxidizing cystamine. To be more specific, since cysteamine is unstable in its free state, it is generally procured as a hydrochloride or a sulfate which is stable. This cysteamine salt is oxidized with hydrogen peroxide and purified to a finished product in the form of cystamine hydrochloride or cystamine sulfate. When the cystamine salt is used as a raw material for medicines and agricultural pesticides, for example, the free cystamine moiety of the salt is the necessary principle component and the hydrochloric acid moiety or sulfuric acid moiety of the salt is more often than not discarded as waste. To obtain the free cystamine, the salt must be neutralized with sodium hydroxide and the product of this neutralization separated and purified.
A method for producing cystamine by reacting 2-aminoethyl hydrogensulfide with sodium sulfide in the presence of sulfur (JP-A-58-35,168) and a method for producing cystamine by reacting 2-aminoethyl hydrogensulfide with ammonium polysulfide (JP-A-60-67,456) have been proposed to date. Since these methods require an excess supply of sulfur, they are at a commercialdisadvantage in giving rise to a large amount of inorganic substance as waste, inevitably necessitating complicate operations in the separation of purified cystamine as the end product from the reaction mixture, and requiring a huge amount of time exceeding 30 hours.
As an approach to the production of an alkylene oxide adduct of cystamine, the reaction of a relevant disulfide-containing dihalogen compound with diethanolamine as represented by the following formula has been proposed (USSR Patent No. 540,862). ##STR2##
Since this method comprises a deoxidation reaction it requires the supply of diethanol amine in an excess amount of preferably not less than 4 mols. It does not itself constitute a commercially satisfactory solution because the product of the reaction contains an alkylene oxide adduct of cystamine and a large amount of diethanol amine salt and the reaction consequently involves a complicated step for purifying the product. A method for producing a nitrogen-containing disulfide by reacting a nitrogen-containing halogenated hydrocarbon with sodium thiosulfate thereby forming a bunte salt and further heating the reaction product in an acidic state as represented by the following formula has been proposed (JP-A-5-70,427). ##STR3##
In accordance with this method, since the nitrogen-containing disulfide obtained by the reaction is present in the form of a hydrochloride or a sulfate, it requires a neutralization treatment and the product of this neutralization necessitates an additional complicated purification step because it contains a large amount of an inorganic salt. Since the reaction gives rise to harmful SO.sub.2 gas, this harmful gas requires a discarding or recovery step. Thus, this method is not a satisfactory solution from a commercial point of view. Further, a method for producing a nitrogen-containing disulfide by first synthesizing a thiuronium salt from thio-urea and a nitrogen-containing hydrocarbon and then hydrolyzing this thiouronium salt in a basic state has been proposed (JP-A-53-95,630). Since this method produces a large amount of waste as a by product, the step for purifying the reaction product is complicated and the yield is only in the neighborhood of 15%. The reaction of cystamine with an alkylene oxide by dint of the reactivity of amine with epoxy has been well known in the industry concerned. Since the cystamine which is generally obtainable is in the form of cystamine hydrochloride or sulfate, the hydrochloric acid moiety or sulfuric acid moiety of the salt must be refined by neutralization in prior to the reaction.
In recent years, as a consequence of the rapid development of various metal processing techniques, the lubricants used in the processing of metals have been improved in a wide variety of properties.
Heretofore, water-insoluble lubricants have been used for lubricating machines for processing metals. They use mineral oils as a basis and incorporate therein oiliness enhancers (such as animal fats and vegetable oils and surfactants), chlorine type extreme pressure agents (such as chlorinated paraffins and chlorinated oils and fats), and sulfur type extreme pressure agents (such as sulfide oils and fats and sulfide olefins). They have numerous drawbacks such as the imposition of regulations of Fire Prevention Laws because of the composition, adhesion of the lubricant to the metallic surfaces under processing, difficulties encountered separating adhering chips, and defiling the shop interior with lubricant.
For the purpose of eliminating these drawbacks, various water-soluble lubricants have been developed. These lubricants, are at a disadvantage in offering inferior extreme pressure effects, impairing machines and tools in terms of service life and operational accuracy, in ability to control microorganisms, becoming putrid and consequently failing to withstand protracted use. These lubricants eventually exhibit corrosiveness to metals, and induce growth of rust on processed parts and processing devices. At times, the water-soluble lubricants are used mixed with various additives intended to overcome such drawbacks as mentioned above. These mixed lubricants, however, are not fully satisfactory in performance.
This invention, has an object of providing a method for permitting cystamine which is useful as a raw material for medicines and agricultural pesticides to be produced in a free state, by a simple procedure, in high yield, and with ideal qualities advantageous from a commercial point of view.
Another object of this invention is to provide an economically advantageous method for permitting an alkylene oxide adduct of cystamine which is useful for water-soluble lubricants, photographic reagents, antibacterial agents, can cleaning agents, and rust-removing agents to be commercially produced in a free state, in high yield, and by a simple procedure.
Yet another object of this invention is to provide an additive for an aqueous lubricant avoiding the drawbacks of the conventional aqueous lubricant and excelling in quality and also provide an aqueous lubricant.